Apparatus and method for magnetising materials

Abstract

An apparatus is disclosed for inducing magnetism in a flowstream of at least partially magnetisable, dry particulate feed material, in order to effect a subsequent particle classification. The dry separation stage is located proximal to the magnetic induction apparatus, in the form of a treatment chamber 10 with a plurality of spaced-apart magnets 16, 18 located adjacent to, and moveably displaceable along the length of both an upper and a lower side region of the treatment chamber 10, to generate a localised magnetic induction field zone. Conveyer belts 22, 24 carrying the dry particles move across each of the outer faces of the magnets 16, 18 on both sides of the chamber 10, but at differential relative velocities to each other, creating a region of air-particle fluidisation and agitation within the treatment chamber 10 and then a physical separation of the particulate feed material can occur based upon their susceptibility to magnetic induction.

1 - 27 . (canceled) 
     
     
         28 . An apparatus arranged for inducing magnetism in a flowstream of at least partially magnetisable, dry particulate feed material, in order to effect a subsequent particle classification thereof, in use the flowstream being fed into a dry separation stage which is located proximal to said magnetic induction apparatus, the apparatus comprising:
 a treatment chamber with an inlet and an outlet, through which the flowstream respectively enters and exits the treatment chamber; and   a plurality of spaced-apart magnetic sources located adjacent to, and moveably displaceable in the same direction along the length of both an upper and a lower side region of the treatment chamber, such that, during said movement, a respective magnetic source from each of the upper and lower side regions forms a pair of magnetic sources which are aligned in opposing relation to one another, and laterally spatially positioned apart with respect to one another, in use each of said pairs of magnetic sources generating a localised magnetic induction field zone; and   said upper side region of the treatment chamber being defined by at least one of a moveable first surface element which is configured in use to move over a face of said spaced-apart magnetic sources which are located thereabove, and said lower side region of the treatment chamber being defined by at least one of a moveable second surface element which is configured in use to move over a face of the spaced-apart magnetic sources which are located therebelow;   wherein during operation of the apparatus:
 the second surface element transports the flowstream of dry particulates into the treatment chamber via the inlet; and 
 once inside the treatment chamber, the relative rate of motion of the first surface element with respect to the magnetic sources at the upper side region of the chamber is greater than the relative rate of motion of the second surface element with respect to the magnetic sources at the lower side region of the chamber, thereby creating a region of air-particle fluidisation and agitation within the treatment chamber due to physical separation of the particulate feed material from the second surface element; and 
   the combined effect of air-particle fluidisation and agitation during exposure to said localised magnetic induction field zones generated by said respective pairs of magnetic sources, results in a physical classification of said particulates, based upon their susceptibility to magnetic induction, such that:
 a feed material fraction with high susceptibility to magnetisation is retained at the first surface element due to a preferential attraction to the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber; 
 a feed material fraction with medium susceptibility to magnetisation is repelled by the pairs of spaced-apart magnetic sources which are located at both the upper and lower side regions of the treatment chamber, ultimately is retained at the second surface element in the regions of low magnetic intensity located between the pairs of spaced-apart magnetic sources in the treatment chamber; and 
 a feed material fraction with low susceptibility to magnetisation is ultimately retained at the second surface element in a region adjacent the spaced-apart magnetic sources which are located at the lower side region of the treatment chamber to which it is attracted, as well as due to repulsion by the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber. 
   
     
     
         29 . An apparatus as claimed in  claim 28 , wherein the plurality of spaced-apart magnetic sources located adjacent to both the upper and lower side regions of the treatment chamber are respectively operably coplanar whilst being laterally spatially positioned apart, in use. 
     
     
         30 . An apparatus as claimed in  claim 28 , wherein the plurality of spaced-apart magnetic sources are connected to a respective moveable support element, operable in use to move the magnetic sources along the length of the upper and/or lower side regions of the treatment chamber by means of an associated drive mechanism, wherein the moveable support element(s) and associated drive mechanism(s) are connected to a frame which is positioned in fixed relation to the treatment chamber. 
     
     
         31 . An apparatus as claimed in  claim 30 , wherein at least one of the moveable support elements is operably moveable by means of an adjustment mechanism, in use to adjust the lateral spatial distance between the magnetic sources which are aligned in opposing relation with respect to one another at the treatment chamber, to thereby reduce the intensity of the localised magnetic field zones thereat. 
     
     
         32 . An apparatus as claimed in  claim 30 , wherein the moveable support element used to move the magnetic sources along the length of the lower side region of the treatment chamber is operably moveable by means of an adjustment mechanism, in use to adjust the lateral spatial distance of those magnetic sources with respect to the second surface element, to thereby reduce the intensity of the localised magnetic field zone experienced at the second surface element. 
     
     
         33 . An apparatus as claimed in  claim 30 , wherein the plurality of pairs of magnetic sources which are aligned in opposing relation with respect to one another at the treatment chamber, and which deliver the highest intensity of localised magnetic field zones thereat, are spaced at a pre-determined distance apart from an adjacent magnetic source along the length of each respective moveable support element such that in use, a zone of relatively low magnetic intensity is operably achieved midway along that predetermined distance between each of the adjacent magnetic sources. 
     
     
         34 . An apparatus as claimed in  claim 30 , wherein each moveable support element comprises an endless loop of a support material which is operably connected to at least two moveable support roller(s) about which the endless loop turns, and wherein each endless loop is operated by the associated drive mechanism in use. 
     
     
         35 . An apparatus as claimed in  claim 28 , wherein the plurality of spaced-apart magnetic sources located adjacent to the upper and the lower side regions of the treatment chamber are moveably displaceable at the same relative rate of motion, in use. 
     
     
         36 . An apparatus as claimed in  claim 28 , wherein the maximum lateral spatial distance between the first and second surface elements with respect to one another is determined by the spatial position of the plurality of magnetic sources at the upper and lower side regions of the treatment chamber, since the respective first and second surface elements are arranged to slidingly move over an exposed face of each magnetic source. 
     
     
         37 . An apparatus as claimed in  claim 28 , wherein the, or each, first and second surface elements comprise an endless loop which is operably connected to a respective moveable support means, operable in use to move the surface elements along the length of the upper and/or lower side regions of the treatment chamber by means of an associated surface element drive mechanism, wherein the moveable support means and associated drive mechanism are connected to a frame which is positioned in fixed relation to the treatment chamber. 
     
     
         38 . An apparatus as claimed in  claim 37 , wherein each moveable support means comprises an endless loop of a support material which is operably connected to at least two moveable support roller(s) about which the endless loop turns, and wherein each endless loop is operated by the associated surface element drive mechanism in use. 
     
     
         39 . An apparatus as claimed in  claim 28 , wherein the, or each, first and second surface elements are moveably displaceable in the same direction, in use. 
     
     
         40 . An apparatus as claimed in  claim 28 , wherein the, or each, first and second surface elements are formed from a resilient, hard-wearing material of construction, capable of supporting abrasive finely powdered ore material. 
     
     
         41 . An apparatus as claimed  claim 28 , wherein the, or each of the, first surface element(s) is moveably displaceable at a rate of motion which is approximately 0.2-1.0 metres/second faster than the rate of motion of the spaced apart magnetic sources at the upper side region of the treatment chamber and optionally wherein the, or each of the, second surface element(s) is moveably displaceable at a rate of motion which is approximately 0.0-0.2 metres/second faster than the rate of motion of the spaced apart magnetic sources at the lower side region of the treatment chamber. 
     
     
         42 . An apparatus as claimed in  claim 28 , wherein the plurality of spaced-apart magnetic sources includes at least one of: permanent magnetic materials; and sources formed of electromagnetic materials which are externally powered in order to induce magnetism, in use. 
     
     
         43 . An apparatus as claimed in  claim 28 , wherein the feed material fraction with high susceptibility to magnetisation includes ferromagnetic particulate materials, the feed material fraction with medium susceptibility to magnetisation includes paramagnetic particulate materials, and the feed material fraction with low susceptibility to magnetisation includes diamagnetic particulate materials and optionally wherein the feed material fraction with low susceptibility to magnetisation may include diamagnetic particulate materials which also contain unliberated ferromagnetic and/or paramagnetic material therewithin. 
     
     
         44 . An apparatus as claimed in  claim 28 , wherein the feed material fraction with high susceptibility to magnetisation is caused to be physically separated from the first surface element in a region outside of the treatment chamber, and once there are no spaced-apart magnetic sources located adjacent thereto. 
     
     
         45 . An apparatus as claimed in  claim 28 , wherein the feed material fraction with medium susceptibility to magnetisation is caused to be physically separated from the second surface element in a region outside of the treatment chamber, and once there are no spaced-apart magnetic sources located adjacent thereto. 
     
     
         46 . An apparatus as claimed in  claim 28 , wherein the feed material fraction with low susceptibility to magnetisation is caused to be physically separated from the second surface element in a region adjacent to, but outside of the exit of the treatment chamber, where the endless loop turns to travel in an opposite direction. 
     
     
         47 . A method for inducing magnetism in a flowstream of at least partially magnetisable, dry particulate feed material, and effecting a subsequent particle classification thereof using a dry separation apparatus which is located proximal to a magnetic induction apparatus, wherein said apparatus comprises:
 a treatment chamber with an inlet and an outlet, through which said flowstream respectively enters and exits the treatment chamber in use; and   a plurality of spaced-apart magnetic sources located adjacent to, and moveably displaceable in the same direction along the length of, both an upper and a lower side region of the treatment chamber, arranged in use so that when pairs of laterally separated magnetic sources, one from each of said upper and lower side regions, are located in opposing facing alignment with one another, a localised magnetic induction field zone is generated therebetween; and   a first surface element which, in use, moves over faces of the plurality of spaced-apart magnetic sources located at the upper side region, and a second surface element which, in use, moves over faces of the plurality of spaced-apart magnetic sources located at the lower side region;   the method comprising the steps of:   following a transfer of particulate feed material onto the second surface element, causing said second surface element to transport said flowstream of particulate feed material into the treatment chamber via the inlet; and   setting the rates of motion of
 (a) the first surface element 
 (b) the magnetic sources at the upper side region of the chamber, 
 (c) the second surface element, and 
 (d) the magnetic sources at the lower side region of the chamber, 
   
       so that the relative rate of (a) to (b) is greater than the relative rate of (c) to (d), thereby creating region(s) of air-particle fluidisation and agitation within the treatment chamber, due to physical separation of the particulate feed material from the second surface element;
 wherein the combined effect of air-particle fluidisation and agitation during exposure to said localised magnetic induction field zones generated by said respective pairs of magnetic sources, results in a physical classification of said particulates, based upon their susceptibility to magnetic induction, such that:
 a feed material fraction with high susceptibility to magnetisation is retained at the first surface element due to a preferential attraction to the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber; 
 a feed material fraction with medium susceptibility to magnetisation is repelled by the pairs of spaced-apart magnetic sources which are located at both the upper and lower side regions of the treatment chamber, and ultimately is retained at the second surface element in a region of low magnetic intensity located between the pairs of spaced-apart magnetic sources in the treatment chamber; and 
 
 
       a feed material fraction with low susceptibility to magnetisation is ultimately retained at the second surface element in a region adjacent the spaced-apart magnetic sources which are located at the lower side region of the treatment chamber to which it is attracted, as well as due to its repulsion by the spaced-apart magnetic sources which are located at the upper side region of the treatment chamber.